Cryosurgery

What is cryosurgery?

Cryosurgery (or cryotherapy) is the application of extreme cold to destroy abnormal or diseased tissue. The term comes from the Greek "cryo", meaning icy cold, and the word “surgery”, meaning "hand work." Cryosurgery is used to treat several diseases and disorders, especially skin conditions.

Cryotherapy is another term used for this treatment; however, this term is also used in the application of cold to inflamed tissue to aid healing, not destroy tissue. So, to be clear, this handout will only use the term cryosurgery to refer to the process of using cold to destroy tissue.

Cryosurgery has been used for over two hundred years. The application of intense cold kills the targeted tissue and numbs the surrounding sensory, reducing pain and discomfort. In humans, this technique is often used to treat patients with intractable cancer, to reduce pain and discomfort by temporarily numbing sensory nerves. It is also used in humans to treat liver and prostate cancer, cervical cancer, and hemorrhoids, along with a variety of skin conditions and tumors.

In animals, the technique is used to treat tumors in locations where conventional surgery would be difficult or impossible, such as certain tumors of the mouth. Or it may be used where the analgesic/anesthetic properties of the technique would be useful, such as the removal of tumors or lesions that the animal is constantly biting, licking, or scratching; tumors or infected, itchy lesions in elderly patients considered high risk for general anesthesia and prolonged surgical techniques. The intense cold also kills bacteria and other germs, which is particularly helpful when dealing with infected tissues.

How is cryosurgery done?

Cryosurgery uses freezing temperatures to destroy cells in the target tissues. Most of the body’s cells are comprised of about 70% water, so when they are subjected to freezing temperatures, ice crystals form inside the cells, causing them to tear and rupture. Additional cellular and tissue damage occurs when blood vessels supplying the diseased tissue freeze.

"Cryosurgery uses freezing temperatures to destroy cells in the target tissues."

Cryosurgery is often done with liquid nitrogen. The super-cooled liquid nitrogen is sprayed on the diseased tissue, circulated through a tube called a cryoprobe, or simply dabbed on with a cotton or foam swab.

Is cryosurgery painful?

Anyone who has been frostbitten can confirm that freezing is painful. To reduce pain associated with cryosurgery, your pet may need local anesthesia, sedation or general anesthesia. If future cryosurgery is necessary at the same location, it may be possible without the use of any further anesthetics due to the inherent analgesic/anesthetic effect of the procedure.

Once freezing has occurred, the tissue slowly dies and falls away. In some moist sites such as the mouth and the anus, the tissue may liquefy and look green and gangrenous. Gentle bathing of the area will remove much of the dead and sloughing tissue. There is sometimes a foul odor from the affected tissues. Despite the unpleasant appearance, there is no discomfort because of the temporary anesthetic effect on nerve endings. In more advanced or serious conditions, multiple cryosurgery treatments may be required. 

How effective is cryosurgery?

In many cases, cryosurgery can be curative, depending on the condition and the site. Small warts and small skin tumors are usually cured with just one cryosurgery session. Tumors in the mouth often go into remission after one treatment and cause no further trouble. Cryosurgery is also sometimes used for the removal of aberrant or extra eyelashes (distichiasis); this procedure has a high success rate.